Nitrocellulose composition



v "UNITED STATES PATENT OFFICE.

JOHANNES M. KESSLER, OF WEST ORANGE, NEW JERSEY, ASSIGNOIR TO I. Di:PON'I m: NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OFDELA.

Patented Nov. 2, 1920:

WARE. NITROGELLULOSE COMPOSITION.

1,357,876. ,Specification of Letters Patent, No Drawing. Applicationfiled December 6, 1919. Serial No. 348,047.

To all whom it may concern:

Be it known'that I, JOHANNES M. Knssnnn,

. a citizen of the United States, and a resident of West Orange, in thecounty of Essex and State of New Jersey, have invented certain new anduseful Nitrocellulose Compositions,

of'which the following is a specification.

This invention relates to nitrocellulose compositions containing as asoftening facture of pyroxylin plastics is the substance used as thesoftening or conditioning agent for the cellulose ester. Although thepatent literature discloses a very large number of substances assubstitutes for camphor, only a small number have found practical.application. Only a few of these substances show any superiority overc'amphor, and in these cases the difference is usually insufficient tomake up for their much higher cost. About the only one at presentavail-' able in this country is triphenylphosphate which is employed toa limited extent in the nitrocellulose plastic industry, and then onlyin connection with camphor.

The scarcity and high cost of camphor has led me to investigate thesuitability of various substances as camphor substitutes which have notheretofore been suggested for this purpose; as a result of thisinvestigation I have discovered that cellulose ester sheets and filmshaving excellent physical and chemical properties from the standpoint oftheir use in the arts may be obtained by using as a softener any one ofseveral classes of substances which may be produced from available rawmaterials at a reasonably low cost. I

One of these classes of substances which I have found to be suitable ascamphor substitutes, and to which in combination with nitrocellulose,the present application is directed, comprises the esters of acyloxydealkyl or aryl esters.

rivatives of aliphatic acids, and especially of monobasic aliphaticacids containing more than three carbon atoms. The acyl group ispreferably either an aliphatic group with a small number of carbon atomssuch as formyl, acetyl, and propionyl, or a carbocyclic acyl such asbenzoyl. As esters there may be used the glycerid of the acyloxy fattyacids or the corresponding prefer those which are readily obtainablesuch as methyl, ethyl, butyl, etc.; and for aryl radicals; phenyl andalphaor betanap hthyl.

he acyloxy derivatives of the lower aliphatic acid esters are notsuitable as camphor substitutes or softeners on account of theirrelative low boiling point, which in the case of eth .l acetylglycollate(3H CO.OCH CO.OC is 179 (1., and in the case of ethyl acetyllactate (GHCO.OCH (CH ).C();()C H is 177 C. at 733 millimeters of mercury pressure.

The esters which I have found to be particularly suitable assofteners'are the esters of acyloxy derivatives of the higher fattyacids. Examples of such substances are the alkyl esters of mono-, di-,or triacetyloxystearic acid, and thealkyl esters of acetyloxy-oleic acid(that is alkyl acetylric'inoleates). The methyl and ethyl esters arepreferred, although the glyceryl esters have the advantage that they canbe obtained di- For alkyl radicals l rectly from the correspondingglycerids xyste'arin, ricinolein. etc.) by acetylation of these oilswith acetic anhy rid.

The properties which the new softeners impart to pyroxylin are veryremarkable.

\Vithout the use of any camphor the methyl and ethyl acetylricinoleatesform with nitrocellulose a pyroxylin plastic having an exceedingly greatflexibility and pliability. v

For example I have found that this plastic material has a Schoppernumber (resistance to cracking on repeated folding) of 170 as comparedwith 20 for regular transparent pyralin or celluloid. I My invention maybe illustrated by the following example: parts (by weight) of drynitrocellulose are kneaded with 32 f parts of methyl acetylridinoleateand from 60 to 70 parts of denatured alcohol at a temperature preferablybetween 40 and 55 C. until the nitrocellulose is properly c01- loided,after which it is put on rolls and through the different operations suchas rolling, cake pressing, sheeting. and seasoning which are well knownin the manufacture of pyroxylin plastics such as pyralin, cellu loid,etc. Suitable amounts of stabilizer, for example urea, and of pigmentsand colors may be mcorporated either during the mix- 7 I ing or therolling operation.

he proportions of the ingredients may be varied considerably Withoutdeparting from my invention;v thus, from 28 to 35 parts of the alkylacetylricinoleate may be combined with 100 parts of the cellulose esterwith good results, although I prefer to have the ratio of nitrocelluloseto softener equal about 3 to 1. A part of the alkylacyloxy aliphaticacid ester may be replaced by camphor or other camphor substitute suchas triphenyl' phosphate;

For producing very flexible films such as are required in the artificialleather industry, a nitrocellulose solution may be prepared inaccordance with my invention having the following composition:

' Nitro'cellulose (preferably dry) l0 parts Ethyl acetylricinoleate- 10to 15 parts Ethyl acetate "10 parts Benzene- 60 parts The proportions ofthe volatile solvents in the above formula may be made greater or lessdepending upon the viscosity desired,

I and part of the ethyl acetate may with ad- Vantage be replaced by ahigher alkyl acenitrocellulose and a softener comprising an ester of anacyloxy derivative of a monobasic aliphatic acid having more than threecarbonatoms'. J

.2. A composition consisting essentially of nitrocellulose and an alkylester of an A composition consisting essentially of acyloxy derivativeof a monobasic aliphatic acid havingmore than three carbon atoms.

naensrc nitrocellulose and a softener comprising an ester of anacetyloxy derivative of a mono basic aliphatic acid having more thanthree carbon atoms.

,4. A composition comprising a cellulose ester and an alkyl esterof anacyloxy derivative of a higher fatty acid.

5. A composition comprising nitrocellulose and an alkyl ester of anacyloXy derivative of a higher fatty acid. I

6. A composition comprising nitrocellulose and a methyl ester of anacyloXy derivative of a higher fatty acid.

7. A composition comprising nitrocellulose, an ester of an acyloxyderivative of a higher fatty acid, and a solvent therefor.

8 A composition comprising nitrocellulose, an ester of an acyloxyderivative of a higher fatty acid, and a solvent therefor comprising analkyl acetate and benzene.

9. A composition comprising nitrocellulose, an alkyl acetylricinoleate,and a solvent for said substances comprising an alkyl acetate andbenzene.

10. A compositioncomprising 3 parts of nitrocellulose and at least about1 part of.

a softener comprising an alkyl ester of an acetyloxy derivative of ahigher fatty acid.

11. A composition comprising-3 parts of nitrocellulose and at leastabout'l part of ethyl acetylricinoleate. I

12. composition comprising nitrocelluloseand an alkyl ester, of anacyloxy derivative of a fatty. acid having 18 carbon atoms.

13. A composition comprising nitrocellulose and an acid.

lose and ethyl acetylricinoleate.

15. A composition consisting essentially of nitrocellulose and asoftener comprising camphor and an alkyl ester of an acyloxy derivativeof a higher fatty acid.

16. A flexible sheet of material comprising nitrocellulose and an alkylester ofan acetyloxy derivative of a higher fatty'acid.

117. A flexible sheet of material comprising nitrocellulose and an alkylester of acetylricinoleic acid.

alkyl ester of an acyloxyoleic I i 14:. A composition comprisingnitrocellu- 18. A flexible material comprisingnitrocellulose and asoftener therefor comprising an alkyl acylricinoleate. I I

lln testimony whereof I affix my signature.

QJOHANNES M. nnssrnn.

